Prevailing definitions of climate are not much different from “the climate is what you expect, the weather is what you get”. Using a variety of sources including reanalyses and paleo data, and aided by notions and analysis techniques from Nonlinear Geophysics, we argue that this dictum is fundamentally wrong. In addition to the weather and climate, there is a qualitatively distinct intermediate regime extending over a factor of ≈ 1000 in scale.

For example, mean temperature fluctuations increase up to about 5 K at 10 days (the lifetime of planetary structures), then decrease to about 0.2 K at 30 years, and then increase again to about 5 K at glacial-interglacial scales. Both deterministic GCM’s with fixed forcings (“control runs”) and stochastic turbulence-based models reproduce the first two regimes, but not the third. The middle regime is thus a kind of low frequency “macroweather” not “high frequency climate”. Regimes whose fluctuations increase with scale appear unstable whereas regimes where they decrease appear stable. If we average macroweather states over periods ≈ 30 years, the results thus have low variability. In this sense, macroweather is what you expect.

We can use the critical duration of ≈ 30 years to define (fluctuating) “climate states”. As we move to even lower frequencies, these states increasingly fluctuate – appearing unstable so that the climate is not what you expect. The same methodology allows us to categorize climate forcings according to whether their fluctuations decrease or increase with scale and this has important implications for GCM’s and for climate change and climate predictions.

The conclusion reads:

Contrary to [Bryson, 1997], we have argued that the climate is not accurately viewed as the statistics of fundamentally fast weather dynamics that are constrained by quasi fixed boundary conditions. The empirically substantiated picture is rather one of unstable (high frequency) weather processes tending – at scales beyond 10 days or so and primarily due to the quenching of spatial degrees of freedom – to quasi stable (intermediate frequency, low variability) macroweather processes. Climate processes only emerge from macroweather at even lower frequencies, and this thanks to new slow internal climate processes coupled with external forcings. Their synergy yields fluctuations that on average again grow with scale and become dominant typically on time scales of 10 – 30 years up to ≈ 100 kyrs.

Looked at another way, if the climate really was what you expected, then – since one expects averages – predicting the climate would be a relatively simple matter. On the contrary, we have argued that from the stochastic point of view – and notwithstanding the vastly different time scales – that predicting natural climate change is very much like predicting the weather. This is because the climate at any time or place is the consequence of climate changes that are (qualitatively and quantitatively) unexpected in very much the same way that the weather is unexpected.

Pielke writes:

There are a series of informative comments on this paper by Judy Curry, Philip Richens, Shaun Lovejoy and others on the weblog All Models are Wrong post

32 thoughts on “'Climate is not what you expect, the weather is what you get'”

Even Gavin on RC acknowledge that regional climate is stochastic at time scales <= 21 years. Which means they are as predictable as the weather. About as predictable as the roulette wheel, on which much of the mathematics and methods behind computer models is based.
If climate science could predict the weather or regional climate days or years in advance, then they could make a lot more money applying this skill at the casino's in Monte Carlo; to predict the next spin of the wheel, the next toss of the coin, or the next turn of the cards.

For example, mean temperature fluctuations increase up to about 5 K at 10 days (the lifetime of planetary structures), then decrease to about 0.2 K at 30 years, and then increase again to about 5 K at glacial-interglacial scales.
==========
In other words, climate does not have a constant standard deviation. This is very important, because it means that the law of large numbers does not apply to climate. You cannot rule out natural variability increasing as time scales increase past 30 years, contrary to the law of large numbers.
Which means that 99.99% of the statistical methods applied to study climate will return incorrect results, because most statistical methods assume a constant deviation.

Shaun seems to be saying that GCMs can produce the statistics of “macroweather” quite well, not that they can actually predict or postdict the actual climate at all.
So there we have it – use GCMs for creating a dummy climate for a fantasy game – that’s fine – but don’t apply the results to any real-world problems or you’ll be screwed.

ferdberple says:
June 29, 2012 at 8:25 am
“Even Gavin on RC acknowledge that regional climate is stochastic at time scales <= 21 years. "
Why do I have the feeling that this "critical" timespan grows larger over time? Hasn't Santer a while ago talked about "17 years of non-warming would falsify the theory"?
Let me guess… It'll be 23 years in 2 years… stop paying these people.

Two comments.
Roger Pielke’s site is one of my favorite and Robert Heinlein is easily my all time favorite writer. My personal opinion is he had it right when he proposed that one’s right to vote should be tied to one’s service. What better way to earn the right to vote than demonstrating the willingness to go in harms way to protect your nation and society. I would acknowledge that such service does not specifically have to be military service. I would include a commitment to such organizationa as the Peace Corps and Americorps. There are many ways to serve.

You expect and get the climate knowing the MACRO-climate drivers….
If you don’t know/guess/model/simulate around….you get nothing but
surprise weather… that is the misery of our times…
but it soon will end….JS

This correlates with the data I’ve been looking at recently:
For example, Washington State:
“The thing that struck me about this graph is that previous 5 years were not hotter than many, many other periods. By not hotter I mean the positive anomalies were not larger. What made the previous 5 years “warmer” was the absence of really large negative anomalies. The recent 5 year period saw the first -5F anomaly since 1995.”http://sunshinehours.wordpress.com/2012/06/24/usanoaa-5-year-averages-plotted-using-all-montly-anomalies/

Dr. Pielke Sr. as almost always, is insightful and on the right scientific analysis track. Now if we can figure out how to cool off all the talking heads maybe some scientific progress can be achieved.

“Regimes whose fluctuations increase with scale appear unstable whereas regimes where they decrease appear stable.”
Now there is some food for thought. Does a “regime” whose amplitude diminishes to 0 when the timescale dial is turned far enough have any meaning?
Power spectra would be good. What about the rather impressive 60 year harmonic shown by
L.B. KLYASHTORIN, A.A. LYUBUSHIN?

The whole city (Newcastlew upon Tyne) ground to a halt yesterday. We had thunder, lightning and rain, there was a lightning strike on the Tyne bridge (it can be Googled if anyone is interested). The drains could not cope with the amount of rain that fell and underpasses under main roads were waist deep in water. The reason the city ground to a halt was because drians blew off cast iron lids and the roads lifted due to the force of the water. I spoke to many people who talked about this type of weather being very severe. They were surprised when I told them that this happens in Florida on a daily basis at this time of the year, Florida’s infrastructure was built with to cope with this, ours isn’t since it is rare.
The conditions we had were exactly the same as occur in Tropical regions, warmth near the ground and cool air much higher up.

Then again at the right time scales, repeating patterns every 6558 days for the past 73 years, are in phase enough to forecast daily weather at about 65% accuracy for precipitation, and hitting the daily temps within 3 degrees 23% of the time, the forecasts for the current cities and airport stations based on past cycles are running on average 3.26 degrees F lower than the actual current temps due to the average of UHI effects.
Now have posted maps for all of North America, and Australiahttp://www.aerology.com/?location=Australia&mapType=Tmax&date=6%2F29%2F2012

I am glad to see Shaun’s and Daniel’s paper and I congratulate them–particularly for the catchy title. You may also see an older version of negation of the same dictum in my paper “Hurst-Kolmogorov dynamics and uncertainty” (see http://itia.ntua.gr/1001/ for the 2011 paper – page 492 or pages 23-24 of the preprint; see also http://itia.ntua.gr/944/ for the 2010 predecessor presentation, slide 45).

Wow, no one jumped all over the original quote or who wrote it. Twain or Heinlein is good enough for me, I never met either of them, but I’ve read both. If someone can’t resist jumping, it might as well be me.
From http://quoteinvestigator.com/2012/06/24/climate-vs-weather/ comes this interesting candidate:

The earliest evidence QI has located of an expression closely matching the questioner’s quotation was published in a textbook from 1901 called “Outlines of Physiography” by the geographer Andrew John Herbertson [OPAH]:
By climate we mean the average weather as ascertained by many years’ observations. Climate also takes into account the extreme weather experienced during that period. Climate is what on an average we may expect[,] weather is what we actually get.

They also have a source from Heinlein, but not Twain. Not surprisingly, Heinlein gave the comment to Lazarus Long:

In 1973 Robert Heinlein released the novel “Time Enough for Love” which included two intermission sections designated “The Notebooks of Lazarus Long”. Heinlein using the persona of Lazarus Long wrote many phrases and aphorisms, and some were Twain-like. One adage closely matched the questioner’s [RHTL]:
Climate is what we expect, weather is what we get.

I’m sort of amused that ‘around’ 30 years is the phase length of the Pacific Decadal Oscillation, and that approximately 3 solar cycles fit in the general gauge. Alternate phenomena in each solar cycle, such as solar cosmic waves, with three solar cycles in a PDO phase, can generate alternating effects in the alternate phases, Daughter predominant and Son predominant.
==========

Seems rather trivial to me.
Temperature fluctuations increasing to 10 days is a function of the size and speed of movement of the mid-latitude high pressure systems. Winds are from the north on one side and the south on the other side.
As for predicting macroweather. Here in the southern hemisphere on the western side of Australia, the 10 day forecasts are pretty good. When Pielke says macroweather forecasts aren’t good, I suspect he is referring to the more chaotic NH weather systems.

The supposed quote from Heinlein, who had some very dodgy political opinions to my mind that are actually well suited at this site, was by Mark Twain. Can’t get fact’s right. Stopped looking here for a spell and find you’re all as wronged headed as ever. Less science. What’s going on Robert? It’s supposed to a science blog

Just to add, all models are wrong? Really? Do you actually do science? Such tosh. Think this site is so well visited for the risibility of the arguments. Good articles mostly but the comments that follow. Not science.

@Jim R:
I’ve googled the phrase and checked the Quote Investigator site at http://quoteinvestigator.com/2012/06/24/climate-vs-weather/
That quote isn’t found in Twain’s writings. What is found is a quote from a student’s test paper, who said, “Climate lasts a long time, weather lasts a few days.” That saying was polished and buffed a bit in the direction of the current maxim, but apparently wasn’t put into its “neat” current form until Heinlein reworded it.

Heinlein had some nasty right wing libertarian thoughts. I’ll go with Twain. He liked folk.
A shame Heinlein wasn’t a scientist ha ha ha you’d have loved him here. Enjoyed Stranger From A Strange Land but it’s all wrong headed for me. That’s the problem I have with some of the folk here, not the science. It’s an ad hom thing. Going back to the Guardian and Skeptical Science!!!!! See you soon xx
[REPLY: This is your sixth comment on WUWT and none of them have been in the least bit substantive. Snark and derision seem to be your stock in trade. Don’t let the door hit you on your way out. -REP]

Jim R,
You appear to be a misfit. You can’t even get Heinlein’s book title right, and you’re arguing about quotes? Go back to the thinly-trafficked Pseudo-Skeptical Pseudo-Science blog where you belong, with all the other anti-science head-nodders. They believe in hockey stick fairy tales over there. And the Guardian makes Pravda look right wing. No wonder they’re rapidly losing readership.

When we finally determine and define a consensus “ideal climate” for Earth’s biosphere, we will have a baseline to which we can assign an anomaly. Until this is done, are we not, just whistling in the wind? Why has this debate never arisen above the noise. GK

Jim R says:
June 30, 2012 at 8:45 am
> Heinlein had some nasty right wing libertarian thoughts. I’ll go with Twain. He liked folk.
Wow, I’d love to see your school research papers. Oh well, in the same vein, Twain is known for plenty of weather quotes, he just didn’t write this one.
If Anthony gives you a chance, I’d like to see your definition of left wing libertarian. We tend to use a grid with economic freedom on one axis and personal freedom on another and your wings don’t work so well on that.
Better yet, get back on topic….
I think it’s important to look a climate changes on pretty much all time scales. Slavish adherence to particular ones, e.g. 30 years, means that you’ll miss things like the Great Pacific Climate shift in the 1970s or our entry into a period of active Atlantic hurricane seasons in 1995.

The climate for each region changes usually four times a year even on the equator. But it is not rigid, you can have all sorts of unusual weather patterns like an Indian Summer and I am absolutely sick of these people who don’t know the basic meteorology. Have they heard of rain shadows? Places within a mile of one another, one gets lots of rain and it misses others. My friend lives about 1.5 km from me in a valley beneath where I live and it would be peeing down with rain where she lives and hardly a drop where I live. We are 3500 ft absl she’s 3250 or so. When it snows it settles where I live, but where she lives it doesn’t because of the UHI effect. Look we lived in Bermuda a narrow group of islands in the South Atlantic. Cold in winter, humid and hot in Summer. We depended on rain water tanks to store water. I lived on Blue Hole Hill a high area looking over the causeway to the island of St.George and airport/American air force base, etc. Dieing for rain, and some of us buying water. We’d watch the rain clouds and shadows and water spouts all around us and then nothing hit land. Yesterday the NSW weather forecast was possible snow on higher peaks and a cold blast. Well it is one of the warmest days we’ve had so far. Somewhere it will be snowing no doubt, but certainly not here. And we are a temperate zone, not like further down the tablelands towards Tamworth that is on average 5C-7C warmer than us – generally. All we need is a big Plinian volcanic eruption say Mt.Vesuvius to make us remember ‘Mother Nature’ controls us whether we will except that or not.

Take a look at “The Man That Corrupted Hadleysburg,” The Mysterious Stranger,” and “Captain Stormfield’s Visit to Heaven.” They are hardly folksy. Heinlein’s quotes actually contain more “up with people” sentiments.

Jim R says:
June 30, 2012 at 8:45 am
> Heinlein had some nasty right wing libertarian thoughts. I’ll go with Twain. He liked folk.
Oh dang! How could I forget?
Do you include “folk” with “congressmen”?
One from http://www.twainquotes.com/Congress.html :

…I never can think of Judas Iscariot without losing my temper. To my mind Judas Iscariot was nothing but a low, mean, premature, Congressman.
– “Foster’s Case,” New York Tribune, 10 March 1873

The lightning there is peculiar; it is so convincing, that when it strikes a thing it doesn’t leave enough of that thing behind for you to tell whether– Well, you’d think it was something valuable, and a Congressman had been there.

I think he would have liked Heinlein.
And, I don’t hold New England thunderstorms in much respect, My CMU days in Pittsburgh had good storms with all the steep valleys for thunder to bounce between.
One major exception – thunderstorms above treeline in NH’s White Mountains. Let’s send our congresscritters there on a fact finding mission.

I bet Jim R probably thinks George Washington had some “nasty, right wing libertarian” ideas. Afterall, GW wrote that government is not reason, it is force.
And while there seem to be people out there who believe that the 2nd Amendment was written so that Americans could enjoy their duck and deer hunting, the fact is that the writers understood that for a free Republic to exist, a government could not possess a monopoly on force.
Makes one wonder when believing in the Constitution and its Amendments denotes someone with nasty, right wing libertarian ideas.

timg56 says:
July 2, 2012 at 1:56 pm
> Makes one wonder when believing in the Constitution and its Amendments denotes someone with nasty, right wing libertarian ideas.
It’s probably all those pasty, left wing fascists that were around in between that make Jefferson, Franklin, and all their cronies so evil.

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